Income includes the revenue streams from wages, salaries, interest on a savings account, dividends from shares of stock, rent, and profits from selling something for more than you paid for it. Income inequality refers to the extent to which income is distributed in an uneven manner among a population. In the United States, income inequality, or the gap between the rich and everyone else, has been growing markedly, by every major statistical measure, for some 30 years.
Wealth inequality can be described as the unequal distribution of assets within a population. The United States exhibits wider disparities of wealth between rich and poor than any other major developed nation.
We equate wealth with “net worth,” the sum total of your assets minus liabilities. Assets can include everything from an owned personal residence and cash in savings accounts to investments in stocks and bonds, real estate, and retirement accounts. Liabilities cover what a household owes: a car loan, credit card balance, student loan, mortgage, or any other bill yet to be paid.
In the United States, wealth inequality runs even more pronounced than income inequality.
The Gini Index
The Gini Index is a summary measure of income inequality. The Gini coefficient incorporates the detailed shares data into a single statistic, which summarizes the dispersion of income across the entire income distribution. The Gini coefficient ranges from 0, indicating perfect equality (where everyone receives an equal share), to 1, perfect inequality (where only one recipient or group of recipients receives all the income). The Gini is based on the difference between the Lorenz curve (the observed cumulative income distribution) and the notion of a perfectly equal income distribution.